Storage coil with air gap in core

Abstract

A storage coil for flux converters or low setting control elements is disclosed. The storage coil has a non-linear d-c bias characteristics associated with a ferrite core. The ferrite core may be a shell core, E core, RM core and U core, with an air gap formed between adjacent end faces of core parts, the adjacent end faces being oriented toward each other to provide a contact area without an air gap less than the overall cross-sectional area of the core and air gap of varying spacing occupying the area remaining between the contact area and the overall cross-sectional area.

What is claimed is; 
     
       1. A storage coil of the type used for flux converters and low setting control elements, having a non-linear d-c bias characteristic and magnetizable core parts, in particular a shell core, E core or RM core having a signal winding on central legs thereof and including an air gap formed between adjacent end faces of the central legs of said core parts, the inductance of said coil being substantially determined by said signal winding and said core, characterized in that in a region of said core where the adjacent end faces of said central legs are oriented toward each other, one of said end faces is completely planar and the other is only partially planar so that a central area of said region has a cross-sectional area less than the total cross-sectional area of said region and has no air gap between said end faces and the remaining area corresponding to the difference between said central area and said total cross-sectional area of said region has an air gap of varying height which is symmetricaly disposed about said central area irrespective of rotational positioning of said core parts with respect to each other. 
     
     
       2. A storage coil according to claim 1, wherein at least one of the mutually adjacent end face regions of the core parts has the form of a truncated cone. 
     
     
       3. A storage coil according to claim 1, wherein at least one of the mutually adjacent end face regions of the core parts is formed as a truncated cone having an angle in the range of five degrees to sixty degrees between the plane of the end face and the slope of the inclined portion producing the varying air gap space. 
     
     
       4. A storage coil according to claim 1, wherein at least one of the mutually adjacent end face regions of the core has inclined portions sloping away from the opposite sides of the first area. 
     
     
       5. A storage coil of the type used for flux converters and low setting control elements, having a non-linear d-c bias characteristic and magnetizable core parts, in particular a shell core, E core or Rectangular Modular core having a signal winding on central legs thereof and including an air gap formed between adjacent end faces of the central legs of said core parts, said central leg end faces being oriented in an opposed relationship toward each other, the inductance of said coil being substantially determined by said signal winding on said core, wherein: one of said opposed end faces has a completely planar surface and the other of said opposed end faces has a surface with only a single, centrally located, planar portion so that in the area between said planar portions of said end faces no air gap exists and between the remaining portions of said opposing end faces an area having an air gap of varying height exists which is symmetrically disposed with respect to said area of no air gap irrespective of rotational positioning of said core parts with respect to each other.